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    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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    <script>
        var Singleton = (function(){
            var instance 

            function User(name,age){
                this.name = name
                this.age = age
            }

            return function(name,age){
                if(!instance){
                    //创建实例
                    instance = new User(name,age)
                }
                return instance
            }
        })()

        
    </script>
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